1. Field of the Invention
The present invention relates to a gas vapor control system, and more particularly to a gas vapor control system and a method for reducing fuel consumption and improving purification efficiency of a catalyst.
2. Description of Related Art
Generally, main pollution materials that are included in exhaust gas are hydrocarbon, carbon monoxide, and nitrogen oxide, and a catalyst apparatus is used to reduce such pollution materials.
The catalyst apparatus oxidizes or reduces the pollution materials that are included in the exhaust gas and transforms the pollution materials to harmless nitrogen, carbon dioxide, and moisture. However, the catalyst apparatus has a characteristic that accumulates oxides when the oxides are larger than a predetermined value during an oxidation/reduction reaction.
When the engine comes to a stop for a long time, the catalyst apparatus is exposed to oxides of the atmosphere and oxygen storage capability thereof decreases. Further, as the oxygen storage capability of the catalyst apparatus increases, the purification capability against nitrogen oxide decreases during the oxidation/reduction reaction.
An amount of fuel that is greater than a theoretical fuel injection amount is supplied during starting so as to solve problems such that the oxide that is captured in the catalyst apparatus is eliminated. However such a system leads to a countervailing increase in fuel consumption.
A vehicle that is equipped with an idle stop and go system stops the engine in an idle state to reduce fuel consumption. The restarting is performed without operating an ignition key in a case in which the driving will of the driver is detected.
However, while the engine repeats stopping and restarting on the idle stop and go system, the oxygen storage capability (OSC) of the catalyst apparatus decreases, and thereby there is a problem in that the purification performance relating to the nitrogen oxide and other pollutants decreases.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.